Doping, which is the intentional introduction of impurities into a material, can improve the metal-semiconductor interface by reducing Schottky barrier width. Here, we present high-quality ...two-dimensional SnS
2
nanosheets with well-controlled Sb doping concentration via direct vapor growth approach and following micromechanical cleavage process. X-ray photoelectron spectroscopy (XPS) measurement demonstrates that Sb contents of the doped samples are approximately 0.22%, 0.34% and 1.21%, respectively, and doping induces the upward shift of the Fermi level with respect to the pristine SnS
2
. Transmission electron microscopy (TEM) characterization exhibits that Sb-doped SnS
2
nanosheets have a high-quality hexagonal symmetry structure and Sb element is uniformly distributed in the nanosheets. The phototransistors based on the Sb-doped SnS
2
monolayers show n-type behavior with high mobility which is one order of magnitude higher than that of pristine SnS
2
phototransistors. The photoresponsivity and external quantum efficiency (EQE) of Sb-SnS
2
monolayers phototransistors are approximately three orders of magnitude higher than that of pristine SnS
2
phototransistor. The results suggest that the method of reducing Shottky barrier width to achieve high mobility and photoresponsivity is effective, and Sb-doped SnS
2
monolayer has significant potential in future nanoelectronic and optoelectronic applications.
Contact resistance is a common issue in organic field-effect transistors (OFETs). Although it is well known that both the contact resistance (<inline-formula> <tex-math notation="LaTeX">{R}_{C} ...</tex-math></inline-formula>) and channel resistance (<inline-formula> <tex-math notation="LaTeX">{R}_{ {Ch}} </tex-math></inline-formula>) are generally gate-dependent, i.e., the resistance values are reduced by increasing gate voltages, the comparison of the gate dependence of <inline-formula> <tex-math notation="LaTeX">{R}_{C} </tex-math></inline-formula> and <inline-formula> <tex-math notation="LaTeX">{R}_{ {Ch}} </tex-math></inline-formula> has rarely been reported. In this letter, we used scanning Kelvin probe microscopy to experimentally measure and compare the gate dependence of the two resistances. The results provide valuable information regarding the charge injection/extraction physics in OFETs. Moreover, the correlation between the gate dependence of the two resistances and the charge transfer characteristic of OFETs was investigated, which can give us some clues to the understanding of the non-ideal transfer curves ("kink" feature) observed in high-mobility OFETs, an issue that has caused both great interest and concern in the community.
In this study, tantalum coatings are deposited by a plasma spraying method aiming at enhancing the biocompatibility of the titanium implant. Tantalum oxide coatings are gained through the thermal ...oxidation of tantalum coatings at different temperatures for photothermal therapy. The effect of thermal oxidation on the morphology, composition, and structure of tantalum coatings has been studied. The UV–VIS–NIR spectra results, cancer therapy effect in vitro, and photothermal conversion properties among the tantalum oxide coatings under varied thermal treatment conditions are compared comprehensively. It has been proven that the tantalum coating treated at 200 °C exhibits the most intense NIR adsorption, the highest photothermal conversion effect, and the most excellent photothermal ablation effect in vitro. The results reveal that incomplete oxidation at a low temperature leads to the formation of oxygen vacancies, which narrow the band gap; this promotes its photothermal conversion ability.
Contact resistance effect is a major issue in organic field-effect transistors (OFETs) because it can severely limit or even dominate the overall performance of OFETs. This is especially true for ...recently developed high-mobility OFETs. Here, we present a systematic study of the contact resistance and its effect on mobility in high-mobility 2,7-dioctyl1benzothieno3,2-b1benzothiophene (C8-BTBT) OFETs by scanning Kelvin probe microscopy. We find that the contact resistance effect can lower the mobility by a factor of four at some temperatures. More interestingly, it is seen that the contact resistance has significant influence on the temperature dependent mobility behavior. The contact resistance-corrected mobility demonstrates stronger band-like transport than the uncorrected mobility in the same temperature range, which has not been reported before.
Physical Unclonable Function (PUF) is a lightweight hardware security primitive and suitable for device authentication in the Internet of Things. However, each strong PUF instance must store at least ...106 reliable challenge-response pairs in the center nodes, which brings an excessive storage overhead since centers connect massive remote PUFs. In this brief, an obfuscation-feedback-shift-register (OFSR) PUF is designed, consisting of certain weak PUF cells working with an obfuscation mechanism. Meanwhile, it efficiently reduces the storage overhead and overcomes the collapse response caused by normal linear-feedback-shift-register, providing higher security. Experiments show OFSR PUF has ideal performance on reliability, uniqueness, uniformity, randomness, and good resistance to machine learning attacks.
A surface-potential-based model is developed for the symmetric long-channel junctionless double-gate MOSFET. The relationships between surface potential and gate voltage are derived from some ...effective approximations to Poisson's equation for deep depletion, partial depletion, and accumulation conditions. Then, the Pao-Sah integral is carried out to obtain the drain current. It is shown that the model is in good agreement with numerical simulations from subthreshold to saturation region. Finally, we discuss the strengths and limitations (i.e., threshold voltage shifts) of the JLFET, which has been recently proposed as a promising candidate for the JFET.
Real-time monitoring of microbial dynamics during fermentation is essential for wine quality control. This study developed a method that combines the fluorescent dye propidium monoazide (PMA) with ...CELL-qPCR, which can distinguish between dead and live microbes for
. This method could detect the quantity of microbes efficiently and rapidly without DNA extraction during wine fermentation. The results showed that (1) the PMA-CELL-qPCR enumeration method developed for
was optimized for PMA treatment concentration, PMA detection sensitivity and multiple conditions of sample pretreatment in wine environment, and the optimized method can accurately quantify 10
-10
CFU/mL of the target strain (
) in multiple matrices; (2) when the concentration of dead bacteria in the system is 10
times higher than the concentration of live bacteria, there is an error of 0.5-1 lg CFU/mL in the detection results. The optimized sample pretreatment method in wine can effectively reduce the inhibitory components in the qPCR reaction system; (3) the optimized PMA-CELL-qPCR method was used to monitor the dynamic changes of
during the fermentation of Cabernet Sauvignon wine, and the results were consistent with the plate counting method. In conclusion, the live bacteria quantification method developed in this study for PMA-CELL-qPCR in
wines is accurate in quantification and simple in operation, and can be used as a means to accurately monitor microbial dynamics in wine and other fruit wines.
Two-dimensional (2D) van der Waals (vdWs) metal-semiconductor heterostructures with atomically sharp interface and matched work functions have recently attracted great attention due to their unique ...electronic and optoelectronic properties. Here we report the vapor phase epitaxial growth of large-scale vertical Sb/WSe
2
metal-semiconductor vdWs heterostructures with uniform stacking orientation. Compared with the growth on SiO
2
/Si substrate, the thickness of Sb nanosheet on WSe
2
can be reduced effectively to monolayer. We construct Sb-WSe
2
-Au asymmetric electrodes photodiode based on the Sb/WSe
2
heterostructures. Electrical transport measurements indicate that the photodiode show obvious rectifying effect. Optoelectronic characterizations show prominent photoresponse with a high photoresposivity of 364 mA/W, a fast response time of less than 8 ms, a large open-circuit voltage of 0.27 V and a maximum electrical power output of 0.11 nW. The direct growth of high-quality metal-semiconductor vdWs heterostructures may open up new realms in 2D functional electronics and optoelectronics.
MD33, a sesquiterpene alkaloid-producing endophyte isolated from
, shows potential medical and industrial applications. To understand the molecular mechanisms of sesquiterpene alkaloids production, a ...comparative transcriptome analysis was performed on strain MD33 and its positive mutant UN32, which was created using Ultraviolet (UV) mutagenesis and nitrogen ion (N
) implantation. The alkaloid production of UN32 was 2.62 times more than that of MD33. One thousand twenty-four differentially expressed genes (DEGs), including 519 up-regulated and 505 down-regulated genes, were identified. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis revealed 139 GO terms and 87 biosynthesis pathways. Dendrobine, arguably the main sesquiterpene alkaloid the strain MD33 produced, might start synthesis through the mevalonate (MVA) pathway. Several MVA pathway enzyme-coding genes (hydroxy-methylglutaryl-CoA synthase, mevalonate kinase, and farnesyl diphosphate synthase) were found to be differentially expressed, suggesting that physical mutagenesis can disrupt genome integrity and gene expression. Some backbone post-modification enzymes and transcript factors were either discovered, suggesting the sesquiterpene alkaloid metabolism in
is a complex genetic network. Our findings help to shed light on the underlying molecular regulatory mechanism of sesquiterpene alkaloids production in
.
A radiation-hardened low-jitter phase-locked loop (PLL) with a low-mismatch charge pump and a robust voltage-controlled oscillator is designed in a 130 nm PD-SOI process. In order to evaluate the ...overall response to single-event effects, the accumulated phase jitter has been put forward, which can exclude the inherent noise floor and accumulate all the radiation-induced noise. Then the single-event sensitivity of the proposed PLL is comprehensively analyzed by heavy ion and pulsed laser tests.
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